Machine Learning Engineer (Ads Optimization)

TL;DR

Machine Learning Engineer (Ads Optimization): Designing and implementing optimization algorithms for auctions, bidding strategies, and pacing to balance advertiser performance and user experience with an accent on marketplace efficiency. Focus on building scalable real-time decision systems, solving complex mathematical optimization problems, and improving ad matching quality.

Location: Remote (United States)

Salary: $185,800 - $303,400 USD

Company

Reddit is a community of communities and one of the internet’s largest sources of information, hosting over 100,000 active communities.

What you will do

• Design and implement optimization algorithms for auctions, bidding strategies, and pacing to optimize CPC, CPA, and ROAS.
• Own the end-to-end system lifecycle from problem formulation and algorithm design to production deployment.
• Translate business and marketplace goals into concrete optimization constraints regarding ROI, revenue, and fairness.
• Improve ad matching and ranking by incorporating new quality and relevance signals into auction decisions.
• Collaborate with Product, Data Science, and Infra partners to integrate new mechanisms into the broader ads ecosystem.

Requirements

• 3–5+ years of experience building and operating production ML systems (5+ years for IC4).
• Strong programming skills in Python, Java, or Go with solid software engineering fundamentals.
• Experience designing scalable data processing systems using Spark, Kafka, Airflow, BigQuery, or Redis.
• Strong mathematical and optimization skills, typically backed by a quantitative degree (Math, Physics, Econ, etc.).
• Must be based in the United States.

Nice to have

• Experience with advertising/auction systems, online marketplaces, or search/ranking systems at scale.
• Familiarity with low-latency production environments and real-time decision systems.
• Advanced degree (MS or PhD) in Computer Science, Machine Learning, or Operations Research.

Culture & Benefits

• Comprehensive healthcare benefits and income replacement programs.
• 401k with employer match.
• Flexible vacation and paid volunteer time off.
• Generous paid parental leave and family planning support.
• Mental health, coaching benefits, and gender-affirming care.